June 7 (Bloomberg) -- Researchers have identified four new
viruses that infect healthy honeybees, potential clues that may
help them better understand why colonies are dying.

Two of the discovered viruses, named Lake Sinai virus
strains 1 & 2, were found to replicate in bees, according to the
paper published today in the journal PLoS One. Over the 10-month
study, the researchers also found that six common honeybee
viruses were most abundant during summer months and that healthy
bees carried fungi and bacteria, as well as mites.

Today’s study is one of the first to pinpoint viruses and
other pathogens present in healthy colonies over time, adding
key information to the understanding of honeybee health, said
Christi Heintz, executive director of Project Apis m., a
nonprofit research group of the beekeeping and agricultural
industries that funded the paper.

“We brought a quantitative view of what real migrating
populations look like in terms of disease,” said Joseph DeRisi,
the paper’s senior study author and a professor of biochemistry
and biophysics at the University of California, San Francisco,
in a statement. “You can’t begin to understand colony die-off
without understanding what normal is.”

Honeybees are needed to pollinate 130 different crops,
representing more than $15 billion each year, according to the
U.S. Department of Agriculture. Fruit-pollinated products are
found in items such as Haagen-Dazs ice cream from Minneapolis-based General Mills. Lip balm made by Burt’s Bees Inc., a unit
of Oakland, California-based Clorox Co., contains wax from the
honeycombs of beehives.

Unexplained Syndrome

Since 2006, the honeybee population has fallen partially
because of Colony Collapse Disorder, an unexplained syndrome
that has killed billions of bees. A United Nations report in
March said that honeybee-colony deaths worldwide may be the
result of reasons as varied as a decline in flowering plant
species to insecticides and air pollution.

Colony Collapse Disorder has no effective antidote. The
disorder is characterized by a massive flight of bees that don’t
return to their hives to die.

The researchers followed 20 colonies in a commercial
beekeeping business as they were transported to pollinate crops
from Mississippi to South Dakota and then to California.

Over the 10 months, the bees were exposed to antimicrobial
treatments, transportation stress and different pollen and
nectar sources, the authors wrote.

Research Findings

The molecular fingerprints of 431 bees were examined to
determine what viruses and other pathogens they carried, said
lead study co-author Michelle Flenniken, a postdoctoral
scientist at the University of California, San Francisco. The
four new viruses are added to 10 already known, she said.

Today’s study will lead to future research, said Heintz,
with Project Apis m., based in Chico, California. Apis mellifera
is a species of honey bee.

“We might isolate some of these viruses and then try to
re-inoculate a colony to see if there is one or a combination of
several that really bring a colony down,” Heintz said today in
a telephone interview. “Are these pathogens working
independently or in combination to bring a colony down? Now we
just know that they’re there, which is a huge step because we
didn’t know it before.”

Dennis vanEngelsdorp, a senior extension associate at the
Pennsylvania State University in State College, said studies are
needed to determine if the viruses and pathogens are harmful.

“It could be some of these organisms found were
beneficial,” vanEngelsdorp, who was not an author on the paper,
said today in an e-mail. “It is not clear to me that the new
viruses were in fact bee viruses; they could have been plant
viruses that were in the pollen that the tested bees ate.”